In 1986, the National Institute of Child Health and Human Development created the Maternal-Fetal Medicine Units (MFMU) Network, consisting of a number of major academic clinical centers, a data coordinating center, and the Institute itself. The purpose of the Network was to conduct clinical research aimed at reducing the risk of adverse pregnancy and infant outcome with the ultimate goal of contributing a body of well-conducted studies on which to base medical decisions in perinatal medicine. At present, the MFMU Network is planning, conducting and analyzing multiple randomized clinical trials and observational studies in various aspects of maternal-fetal medicine such as preterm birth prevention, prediction and prevention of preeclampsia, measures of obstetrical safety and the management of pregnant women with potential risk factors such as subclinical hypothyroidism. The George Washington University Biostatistics Center proposes to continue to serve as the data coordinating center for the Network. Our purpose is to provide expertise and support in study design, study conduct and statistical analysis. We will provide statistical leadership in the design of each research study and in the preparation of interim and final analyses. We will prepare study documents, including protocols, manuals of operations and data forms, and we will continue to provide a comprehensive data processing system including distributed, web and central data entry, data base management and data quality control. We will assist investigators in the preparation of manuscripts and abstracts from study results and we will prepare the final dataset for sharing per MFMU Network policy. We will also provide administrative support such as arrangement of logistical services for provision of study drugs and laboratory assays, maintenance of the MFMU Network website, coordination of meetings, training sessions and outcome reviews. We will manage resources effectively and creatively, so that we can start new studies in a timely manner. The relevance of the proposed research to public health is clear and direct. The results of the Network studies potentially can benefit pregnant women and their children worldwide;for example, by finding methods to screen for problems in pregnancy, by finding maternal treatments that improve children's health, and especially by finding treatments that can help lessen the problem of babies being born too early.